In order to allow a fuel tank to be ventilated or aerated, the tank must be equipped with at least one ventilation valve in a housing and an opening placed on an upper opening of the tank and projecting into the tank. The wall of the valve housing is interspersed with openings so gas or a fuel vapor-air mixture and liquid fuel can flow through the wall. A float that can move from a resting position to a closing position and which carries a sealing element on its upper end has been placed on the valve housing. When the float is in its resting position, the float is located in a lower position in the valve housing, and the sealing element releases the ventilation opening. When the float is in its closing position, the sealing element closes the ventilation opening as soon as a pre-set fuel level is reached, hereinafter named “closing level”. When, for example, fuel is supplied to the fuel tank through a filling pipe during the refilling of the tank, gas cannot escape from the tank through the ventilation opening as soon as the closing level is reached. If refilling continues, the fuel level rises initially inside the tank by accumulating inside the tank and finally in the filling pipe as well, which eventually leads to the turning off of the pump nozzle.
As explained in more detail below, such valves function under a so-called refueling hysteresis. In other words, a relatively large quantity of fuel must be consumed for the fuel level to drop to a level such that the float or its sealing element can release the ventilation opening once again.
Therefore, the task of the present disclosure is to suggest an improved fuel tank for a vehicle that improves on the disadvantage mentioned above.